Again, this about AMD not Intel. Bulldozer has 2x128b FMA pipelines, but they are FMA4. Piledriver is FMA3 (which people will actually use as it is compatible with Haswell). So when you don't use an FMA, you leave half the FLOP/s on the table.

>I'd like to hear people's opinions about AMD's Heterogeneous System Architecture
>(HSA). I am struggling to understand how it is possible to have an ISA-agnostic
>interface (therefore needing a Just-In-Time compiler) >without paying a big performance
>penalty.

LLVM manages quite nicely. As GPUs become more similar to one another, it will be easier to write code that can function well on all architectures.

Also, it may be possible to compile at install time (rather than JITing).

>The whole purpose of heterogeneous computing is to get more >performance
>so why would it make sense to use a Just-In-Time compiler?

JITs may not be required. Even if they are, some JITed languages are quite fast.

>It seems like the vast majority of software vendors that make use of GPUs for computing
>only support Nvidia GPUs (for example, Adobe Photoshop, >Adobe Premiere and Neat
>Video). What does HSA provide that could change this >situation?

Because CUDA is on it's way out. It's a proprietary interface for a company with relatively low market share. Software developers would much rather have something that runs on AMD, Intel and Nvidia GPUs.

Intel can get away with proprietary interfaces, because they have massive market share. The rest of the world really cannot (in the context of PCs). Even there, it's not clear which way Intel will head...OpenCL may be looking very attractive for developers.